Reaction Kinetics Regulation Suppressed Carrier Recombination Loss for High‐Efficient Solution‐Based Antimony Selenosulfide Photovoltaic Devices

Carrier recombination loss within the emerging antimony selenosulfide (Sb₂(S,Se)₃) photovoltaic cells is a critical factor limiting the photovoltaic performance. Herein, the alkaline reducing agent (sodium borohydride, SB) is innovatively employed to manipulate the reaction kinetics, simultaneously achieving deep-level defect passivation and oxide impurity inhibition. Ultimately, a champion power conversion efficiency (PCE) of 10.62% (0.0684 cm²) is gained.

Abstract

Carrier recombination loss within the emerging antimony selenosulfide (Sb₂(S,Se)₃) photovoltaic devices is a critical factor limiting the photovoltaic performance. Herein, a reaction kinetics regulation strategy is reported to simultaneously passivate deep-level intrinsic defect and inhibit the oxide impurities in Sb₂(S,Se)₃ absorber with the help of sodium borohydride (SB). The SB, on one hand due to the alkaline feature, can significantly promote the decomposition of selenourea and Sb₂Se₃ formation, eliminating the deep-level Sb_S1 defects and reducing the V_S defects, and on the other hand, owing to the reducing property, can restore SbO⁺ ions to Sb³⁺, thus inhibiting the Sb₂O₃ formation and improving heterogeneous nucleation with preferable [hk1] orientation. These collective influences have remarkably suppressed carrier recombination loss and strengthened carrier collection with optimal band alignment. Consequently, high-efficient Sb₂(S,Se)₃ photovoltaic devices with an efficiency of 10.62% (0.0684 cm²) are gained, which is comparable to the latest-recorded value of 10.7% (0.0389 cm²). This work provides a feasible reaction kinetics regulation method for suppressing carrier recombination loss of Sb-based chalcogenide materials and supplies precious instruction for preparing high-performance optoelectronic devices.